1. Field of the Invention
The invention relates to an illuminating module for a display apparatus, more particularly to an illuminating module which employs two light sources and which can achieve a relatively high light utilization rate while ensuring compactness and lightness.
2. Description of the Related Art
Conventional display apparatuses require a light source in order to perform beam splitting, modulation, synthesis, image formation, etc. The utilization of light has a direct effect on the quality of the images produced and the size of the apparatus. In terms of the utilization of light, some display apparatuses use a single light source, while others employ a plurality of light sources. This invention is directed to an illuminating module having two light sources for a display apparatus.
FIG. 1 shows a conventional illuminating module including, from left to right, a reflector assembly 11, two light sources 112, a light integrator 12, a polarization state converter 13 and two condensers 14. The reflector assembly 11 includes two juxtaposed parabolic reflectors 111, each of which has a parabolic reflecting surface 113 facing the light integrator 12. The light sources 112 are respectively disposed at focal points of the parabolic reflectors 11. Light rays radiated by each of the light sources 112 are reflected by the corresponding one of the reflecting surfaces 113 to travel in parallel lines toward the light integrator 12. The light integrator 12 converts the light rays from the reflector assembly 11 into evenly distributed light rays for passage through the polarization state converter 13 and the condensers 14 for subsequent projection on a display panel 15 to display desired images.
In the conventional illuminating module 11, although the two juxtaposed parabolic reflectors 111 can reflect the light rays from the two light sources 112, since the light rays reflected by the reflecting surfaces 113 encompass a relatively large area, the sizes of the light integrator 12, the polarization state converter 13, and the condensers 14 have to be correspondingly enlarged in order to achieve an optimum light utilization rate. In addition, more condensers may need to be used. In other words, to effectively utilize the light rays, the conventional illuminating module 11 requires larger or a great number of components, which means higher costs and increased size.
On the other hand, if a smaller light integrator 12 and a fewer number of condensers 14 are used in conjunction with the two parabolic reflectors 111, the light rays reflected by the reflectors 111, which cover a relatively extensive area, cannot be effectively used. In short, the conventional illuminating module 1 cannot achieve compactness with an optimum light utilization rate.
Therefore, the main object of the present invention is to provide an illuminating module for a display apparatus, which employs two light sources and which can achieve a relatively high light utilization rate while ensuring compactness and lightness.
Accordingly, an illuminating module of the present invention is adapted for use in a display apparatus, and includes first and second light sources, curved first, second, third and fourth reflectors, and fifth and sixth reflectors. The first and second light sources are spaced apart from each other in a first direction. The first reflector has a hemispherical first reflecting surface facing in a second direction that is transverse to the first direction, and a first focal point that is coincident with the first light source. The curved second reflector has a hemispherical second reflecting surface that faces in a third direction parallel to the second direction and that is spaced apart from the first reflector in the first direction, and a second focal point that is coincident with the second light source. The curved third reflector has a parabolic third reflecting surface that faces and that is spaced apart from the first reflecting surface in the second direction, and a third focal point that is coincident with the first focal point. The first portion of light rays from the first light source radiates toward the third reflecting surface, while a second portion of the light rays from the first light source radiates toward the first reflecting surface and is reflected thereby to combine with the first portion of the light rays. The curved fourth reflector has a parabolic fourth reflecting surface that faces and that is spaced apart from the second reflecting surface in the third direction, and a fourth focal point that is coincident with the second focal point. A first part of light rays from the second light source radiates toward the fourth reflecting surface, while a second part of the light rays from the second light source radiates toward the second reflecting surface and is reflected thereby to combine with the first part of the light rays. The fifth reflector is disposed between the third and fourth reflectors, and has a planar fifth reflecting surface facing the third reflecting surface in a fourth direction that is transverse to the second direction. The light rays received by the third reflecting surface are reflected thereby to travel in the fourth direction toward the fifth reflector, and the light rays received by the fifth reflecting surface are reflected thereby to travel in a fifth direction transverse to the fourth direction and parallel to an optical axis. The sixth reflector is disposed between the third and fourth reflectors, and has a planar sixth reflecting surface facing the fourth reflecting surface in a sixth direction that is transverse to the third direction. The light rays received by the fourth reflecting surface are reflected thereby to travel in the sixth direction toward the sixth reflector, and the light rays received by the sixth reflecting surface are reflected thereby to travel in a seventh direction transverse to the sixth direction and parallel to the optical axis.